Machines such as automobile, truck or jet engines, compressors and industrial air conditioners, automotive exhaust systems and like dynamic devices generate significant vibration during operation. This vibration will be transmitted directly to support structures with which the dynamic devices is mounted or associated, e.g., an automobile or aircraft frame, a compressor frame, or a floor or rooftop. In order to minimize transfer of vibration from the operating dynamic device to the associated support structure, i.e., isolate the vibrations, it is common to interpose vibration damping and/or isolation means between the dynamic device and the associated support structure. Examples of such vibration damping and/or isolation means would be vibration-absorbing, elastomeric automobile or truck engine mounts placed between the brackets which are used to bolt the engine to the associated auto or truck frame, exhaust hangers, pads interposed between an air conditioner or compressor and a frame or floor and the like.
Vibration damping and/or isolation materials known in the art include vulcanized shapes, e.g., squares, rectangles or cylindrical shapes prepared from vulcanized rubber. These dampening and/or isolation devices can be solid rubber, foamed rubber or solid rubber enclosing a fluid-containing cavity. Suitable rubbers which have heretofore been used in such applications include halogenated and non-halogenated butyl rubber (copolymer of isobutylene with up to 10 wt % isoprene), natural rubber and synthetic elastomeric polymers and copolymers of butadiene.
In addition, EPA 0533746 discloses vibration damping materials based on a vulcanized mixture containing a halogenated copolymer of a C.sub.4 to C.sub.7 isomonoolefin and para-alkystyrene, carbon black, a plasticizer oil and a curing system.
Although natural rubber is an elastomer of choice in some applications because of its superior dynamic properties, i.e., good tensile, modulus and spring rate (stress/strain) properties, the aging and high temperature resistance of cured parts based on natural rubber vulcanizates are poor, thereby limiting the effective life of such parts. For example, engine mounts associated with modern engines must be able to withstand temperatures as high as 150.degree. C. for periods in the range of 1,000 to 5,000 hours without significant loss of dynamic properties, in order to meet current and anticipated automotive standards.